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Aug. 25, 1,925.4

F. R. JOHNSON ELEcTaosTATIc SEPARATION Filed May 1v 1524 5 sheets-sheefz Aug. z5, 1925.

F. R. JovHNsoN ELE CTR OS TATI C S EPARATI ON 5 sheets-sheet@ Filed May 1924 www" In..

F. R. JOHNSON ELECTROSTATI C SEPARATION Filed May 1'? I 1924 5 shets-sheet 5 Aug. 25, 1925. u 1,551,397

Patented Aug. 2s. 1925.

' UNITED .STAT-ES PATENT, OFFICE.

FRED R. JOHNSON, 0F ARLINGTON, MASSACHUSETTS, lASSIG'NOIR, T0 HU'FF ELECTRO- STATIC SEPARATOR COMPANY, ARLINGTON, MASSACHUSETTS, A. CORPORA- TION 0F MAINE.

I ELECTBOSTATIC SEPARATION.

Application mea may 17, i924. serial No. 714,004.

To all whom t may camera.'

Be it known' that I, FRED R. JOHNSON, a citizen of the United States of America, and resident of Arlington, in the county of Middlesex and 'State of Massachusetts,

have invented new' and useful Improve.

ments in Electrostatic Separation, of which the following is a specifica-tion.

This invention relates to electrostatic separation of unlike'particles from a comminuted mass of materials having different characteristics by subjecting the particles vto an electrostatic charging infiuence and then moving the particlesv past' an electrode adapted to deflect the different particles different amounts; andthe invention is particularly useful in that method of separation wherein the particles are charged by a spray electrode as they approach the separating electrode, the particles being supported upon a conducting surface adapted to conduct away a par-t or all of the charges from the particles having greater conduc-` tivity. l

A principal object of the invention is to separate relative large pieces of material such as coke from clinkers Where the ieces may be an incl1 in diameter or larger. owever, the invention is applicable to a wide variety of materials, a few typical uses comprising the separation of iron from zinc, iron from sand, rock and quartz from fluorspar and felspar, 'mica from garnet andq-uartz, uartz from arnet, roots from gum, shale rom rock-sa t, alumina from aluminum, aluminum from gross, abrasives and other electric furnace products, etc. etc. Other ob iects are to separate the ,unlike materials more completely, to reduce the number of stages f ofv separation, to maintain a high density separatin field Without disruptive discharges, to facilitate the adjustment and operation of the separators, to increase the life of the separating electrodes, and generally to improve the art of electrostatic se aration.

or the purpose of illustrating the genus of the invention certain concrete embodiments are shown in the accompanying drawin s in whichig. 1 is' a front elevation of a complete machine;

Fig. 2 is a side elevation of the machine;

Fig. 3 is a vertical longitudinal section of Fig. 1; J

Fig. 4 is an enlarged detailed section corresponding to Fig. 3;

Fig. 5 is a longitudinal section of onel of the separating electrodes and its support.'v

Flg. 6 is a plan view of the separating @and spraying electrodes;

Fig. 7 is a circuit diagram showing one type of circuit connections;

igs. `8 and 9 are transverse and longitudinal sections of a' modified separating electrode;

Figs. 10 and 11 are'similar views of a further modification;

Figs. 12 and 13 are similanviews of still another modification; and

Fig. 14 is a section on line 14-14 of Fig. 13.

'Y he particular embodiment of theinven! tion -cliosen for the purpose of illustration" comprises upright frame members 1, a hoper 2 mounted atthe top of the frame, a eed roller 3 for delivering material from the hopper at approximately uniform rate,

a series of inclined shelves 4- for direct'- ing the material alon a zig-zag path of the separating elec-tro es successively, rollers 5 over which the material passes as it leaves the shelves 4, spray electrodes 6 for charging the particles as they pass over the rollers 5, separating electrodes 7 arranged in vertically staggered relationship forj separating the. materials as they fall from the,

ledges constituted by rollers 5, and hoppers 8 for receiving one class of the unllke particles, the inclines 9 deflecting the other class of particles to the sides of the machine.

drive shaft which is driven by pulley 10 and the rollers 5 are geared together to rotate in unison by means of the tram of gears shown in Fig. 2. The separating electrodes.

-brackets 12 (Fig. 4), the shelves being agitated by means of vertically reciprocating rods 13 carrying arms .14 upon whlch the shelves .rest near the side opposite to The feed roller 3'is mounted directly on the v the ears 12. The rods 13 are guided by brackets 15 secured to the end uprights 16- Ioscillated vertically Aby means of toothed wheels 18 ,upon which the rods rest- (Flg. 3).

Referring tov Figs. 4, and 6each ofv the separating electrodes 7 comprises two heads 19 and 20, which are preferably formedof wood or other insulating material, jour` nalled through ball bearings in brackets 21, which are adjustably mounted by means of thumb screws 22 in the uprights 1, a cylinder 23, also of wood or other insulating material, interconnecting the heads 19 and 20, a plurality of tubes 24 extending between the heads inside the cylinder 23, and a rod 25 extending axially through head 19,-the inner end of the rod being electrically connected tothe tubes 24 and the outer end car.,-

yrying a loose ring 26 which is-connected(to the conductor 27. The pulley 28 is mounted on the projecting end of head 20. 'The electrodes 7.are braced byf-adjustable arms 33 (Fig. 4). The spray electrodes 6 each comprises two metallic stri s 29 mounted in spaced parallel relations ip in grooves in cross-bar 30 which is mounted on swinging arms 31 adjustably mounted on the uprights 1 by means of thumb nuts 32.

The circuit arrangement shown in Fig. 7 includes a mechanical rectifier 35 connected on one side through resistance 36 to the spray electrodes 6 and at the other side to the rollers 5; and a transformer 37 connected through a vacuum rectifier 38 to the electrodes 7 and through a conductor 39 to the rollers 5. The positive sides of the two circuits are connected to the rollers and the negative sides respectively to the electrodes 6 and 7 although the vconnections may be reversed for certain classes of work. By employin two separate circuits the electrodes' 6 and may be charged to different poten-- tials and may be excited at diz'erentfrej quencies of pulsation. For example, vin sweparating coke from clinkers markedly superior results may be attained by charging the spray electrodes 6 at. a potential of approximately 20,000 volts and 125 cycles frequency and the separating electrodes 7 'at al potential of approximately 15,000 volts an cycles frequency. 1 p

The electrode shown in Figs. 8 and 9Comprises a stationary axial support 41 ymounted 1n xed supports 42 and carrying a xed-eccentric contactmember 43 intermediate its ends. Surrounding support 41 are two heads 44 and 45 interconnected by a cylindrical sleeve 46, each of these -parts preferably being formed of wood or other insulating material. Conducting bars 47 extend between ing set `into recesses in heads 44 and 45 insulating strips 47a being mounted between the bars 47. The rotor formed by heads 44 and 45,"sleeve 46, and'bars47, is journalled upon ,rings 48-48 and 49-49 respectlvely fast upon the rotor and the axial support 41. The head 44 is preferably provided with an integral pulley 50 for revolving the rotor as `described in connection with the electrodes 7. The eccentric contact element 43,

contacts with the inner sides of the bars 47 as thebars pass through a predetermined arc of their rotation and conducts the exciting current thereto from the conductor 27 which corresponds to conductor 27 in Fig. 7.

`The electrode shown in Figs. 10 ad 11 is similar to that shown in Figs. fraud 9texcept in that the conductor bars 47 are replaced by tubes 47.

The electrode shown in Figs. 12, 13 and 14 .is'similar to that shown in Figs. 10 and 11 except in that the shaft 60 turns with the rotor and current is conducted to the tubular bars 47 through a stationary contactor 61,

thence through commutator bars 62 mounted i lcircumferentially spaced bars the distribution of klinx. betweenthese electrodes and the rolls 5, where the field is of course most concentrated, is varied as the.bars move past this region. Moreover the area of the shield 23 or 46) which is subjected to the greatest dielectric V stresses is continually lshifted as succeeding sectionsV of the shield move into opposition to the roll 5, thereby relieving the stresses after a brief interval and permitting the use of a much higher field denwithout destroying the dielectric quality of 'the' shield.

This invention, which is the result of long experience and extensive experimentation, makes it possible to separate coke from clinkers J(and other large pieces) up to one inch in diameter andhlgher, whereas it hasnot been ,possible heretofore,- so -far as I am Thus the invention broadens the art of` electrostatic separati-on to include many new fields vheretofore excluded because of size ret strictions and particularly it makes the separation of coke from clinkers commercially feaslble.

aware, electrostatically to separate particles larger than approximately one-quarter inch. 125

Salient features of the invention 'consist in periodically varying` the' distribution. of thestatic eld- (which iseffected by rotatlon of the electrode 7 in the illustrative embodiment), and in pulsating the spray discharge i or the static field, whereby large pieces of material, such as coke and clinkers, may be f separated.

' unlike particles from a comminuted mass of- I claim: 1. The art of electrostatic separation of materials having different characteristics which comprises moving the material over a lcharged surface through a spray discharge of opposite polarity and thence through a static field of said opposite polarity and periodically varying the intensltyof said static eld'. l

2. 'The art of electrostatic separation of i unlike particles from a comminuted mass of lmaterials having different characteristics which comprises moving the material Iover a charged surfacethrough a pulsatingspray discharge of opposite polarity and thence hrough a static field of said opposite poarity.

4. The art of electrostatic separation of unlike particles from va comminuted mass of materials having different characteristics which comprises movin the material over a charged surface throug a pulsatingspray discharge -of opposite polarity and thence through a pulsating static field of said opposite polarity.

-5. The art of electrostatic separationv of .unlike particles from a comminuted mass of materials having different characteristics which comprises moving the material over a charged surface through a pulsating spray discharge of opposite polarity and thence through astatic field of said opposite polarity, and continually varying the distribution of said static field.

6. The art of electrostatic separation fof unlike particles from a comminuted mass of materialsl having different characteristics which compris-iesv moving the material over a charged surface through a pulsating spray discharge of opposite polarity and thence through a pulsating static field 0f said opposite polarity, and continually varying the distribution of said static field.

7. The art of electrostatic separation of unlike particles from a comminuted mass of materials having different characteristics which comprises-moving thematerial over a charged surface through a spray ldischarge of high potential and thence through a pulsatin static field of lower potential.

- .8. he art of electrostatic separation of unlike particles from a comminuted mass of materials having different characteristics which comprisesv moving the material over a charged surface through apulsating spray discharge and thence through a pulsating static field of lower frequency.

9. The art of electrostatic separation of unlike particles from a comminuted mass ofmaterials having different characteristics which comprises moving the material over a charged surface through a pulsating spray discharge of high potential and thenceV through a ulsatingstaticjfield of lower frequency'anil) o 10. The art of 'electrostatic separation of unlike particles from a comminuted mass of materials having different characteristics which comprisesmovin the material over acharged surface throug a pulsating .Spray discharge of high potential, thence through a pulsating static lield/ of lower lfrequency and lower potential, and continually varying the distribution of the static field in the path of the material.-

11. -An electrostatic separator comprising means for feeding' comminuted material over a conducting surface, means for directing a pulsating spray discharge to the malower potential. 'f

terial on said surface, means for subsequently subjecting the -material to a pulsating static field of lower frequency and ldischarge to the material on said surface, Y

.and means including another circuit for sub sequently subjecting the material to a pulsating static field of lower frequency and lowei potential. o

13. A11 electrostatic separator comprising a static electrode, a shieldv for the electrode, means for directing charged particles into' the shieldedinfluence of said electrode, and means for continually changing the electric stress in the shield.

14. An electrostatic separator comprising,-

means for rendering the fieldl more intense on the side of the electrode adjacent the path of the particles, and means for continually shifting the shield to bring dil'l'erent parts into operative position.

16. An electrostatic separator comprising a static electrode, a shield surrounding the electrode, means for directing charged particles past the electrode, and means for roltating the shield to bring different sections between the electrode and particles.

17. An electrostatic separator comprising a static electrode, a shield surrounding the electrode, acharged surface for directing particles past the electrode, and means for rotating the shield to bring different sections between the electrode and particles'. y

18. An electrostatic separator comprising a static electrode, a shield surrounding the electrode, means for directing particles past the electrode, lmeans for directing a spray discharge to the particles oas they approach said electrode, and means for rotating the shield to. bring different sections between the electrode and particles.

19. An electrostatic separator comprising a` static electrode', a shield surrounding the rounding the electrode and' means electrode, and means or'mounting the shield to turn about an axis passing therethrough.

20. An electrostatic separator comprising a static electrode, a cylindricalshield. surfor mounting the shield to revolve about its axis.

421.y An electrostatic separator comprising a static electrode, ashield surrounding thea electrode, and means for rotatably mounting the electrode and shield.

22. A11 electrostatic separator comprising Ia static electrode, a shield surrounding theT electrode, and means for rotatably mounting the electrode and shield toturn abou the axis of the shield. ,Y

23. An electrostatic sep/arator comprising a cylindrical sleeve and` an electrode in the form of a plurality of spaced conductors extending longitudinally of the shield inside thereof.

24. An electrostatic separator comprising a ledge, means for `feeding comminuted material over the ledge, an elongate electrode extendingv along `said ledge in opposition thereto, a shield surrounding the electrode, and a spray electrode opposed to said ledge immediately above said electrode.

25. An electrostatic separator comprising a plurality of electrodes arranged in vertically staggered relationship, superposed shelves for delivering comminuted material to vthe electrodes respectively, alternate shelves being inclined in opposite directions, actuating means bridging the spaces between the superposed shelves, and means common" to the respective shelves, for oscillating said actuating means.

26. A11 electrostatic separator comprising a plurality of electrodes` varranged in vertically staggered relationship,` superposed shelves fordelivering comminuted material to the electrodes respectively, alternate` shelves being inclinedin opposite directions, a vertically reciprocating rod for agitating said shelves,. and a rotary toothed member upon which said rod rests whereby rotation of said member oscillates said shelves.

Signed by me at Boston,-Massachusetts, this 6th day of May, 1924.

FRED nl JoHNsoN. 

